The present invention relates to a novel inflatable multi-layer barrier mounted so as to provide insulation to or within a building. The present invention relates particularly to such a barrier system for use in agricultural buildings, such as barns, livestock or animal housing buildings, greenhouses and the like.
Inflatable vent systems contemplated by the prior art include a cover assembly for sealably permitting the closure and opening of such vent openings by inflating and deflating a horizontal multi-sectional tubular mat assembly which is mounted exteriorly or interiorly to the opening of a building, usually a greenhouse.
There have been a number of mat-like inflatable partition assemblies that have been developed for controlling the ventilation, lighting, humidity and temperature inside a building. Some of these vent assemblies extend across the ceiling of a greenhouse at various heights so as to provide an overlying insulating cover and/or to minimize the air space to be heated. For example, such assemblies are discussed at U.S. Pat. Nos. 4,038,788; 4,290,242; 4,297,813; 4,305,235; 4,318,251 and 4,352,259.
U.S. Pat. No. 4,290,242 describes a plurality of clear polyethylene tubes extending in a spaced adjacent relationship longitudinally across a greenhouse at the edge of a roof that projects beyond the wall. Once again, the system is intended for application in a greenhouse structure.
More specifically, U.S. Pat. No. 4,672,888 describes an expandable mat-like vent closure apparatus comprising a clear inflatable mat, the opposed surfaces being sealed to one another to form a plurality of horizontal tubular members with a plurality of internal air passages connected to one another. A plurality of horizontal tubular membranes are formed from a single sheet sealed together horizontally at various intervals by spot seal.
The disadvantage of this vent closing structure and system is that the membranes are tubular and the points of attachment of the single membrane are spot sealed which cause “valleys” in the membrane barrier structure on both sides.
These “valleys” are points where the insulation value of the barrier is essentially minimal as there is no air barrier between the ambient exterior conditions and the interior of the building, this hindering the ability to optionally and economically control conditions in the building, such as temperature and the like.
In particular, the “valley” structures associated with the spot seals form areas where condensation may accumulate on either side of the barrier structure, again inhibiting the insulation value of the barrier as well as adding weight to the barrier requiring more energy to maintain the barrier inflated or inhibiting or preventing, due to the load, inflation and thus closure of the barrier, requiring the inconvenience of removal of the accumulated condensation for proper function of the barrier system.
Another problem associated with this prior art structure is that due to spot sealing of a single membrane sheet, the structure is lacking in rigidity, being more flimsy and limited in the practical height of the membrane structure which may be achieved by air inflation of the structure. This creates a practical limit as to the size of opening with which the prior art barrier may be used.
The improvement of this invention lies in that the plurality of inflatable hollow membrane structures are cube-like instead of tubular and thus there is increased rigidity, insulating value and no longer a need for spot seals between each tubular membrane. The multi-layer barrier allows for ventilation and prevents heat loss. The multi-layer insulating barrier lies in the gutter of a frame, composed of an upper and lower support, which allows for the movement of the barrier when it is being inflated. As required, there is also a plurality of vertical supports that are mounted to the upper and lower channels and are sufficiently spaced to prevent sagging of the barrier when it is being inflated or deflated.
Another advantage of the present invention is that the cube-like membranes ensure that the barrier is more resilient and durable and thus a greater number of cube-like membranes can be stacked one on top of the other, allowing increase in the practical height of the insulating barrier. The barrier systems existing in the prior art are limited to approximately 5 feet because of the lack of resilience in the inflatable sheet due to its weakness in construction, whereas the present invention will permit a barrier up to approximately double this height.